Add support for OCB mode as per RFC7253
Reviewed-by: Tim Hudson <tjh@openssl.org>
diff --git a/crypto/modes/ocb128.c b/crypto/modes/ocb128.c
new file mode 100644
index 0000000..eca12d7
--- /dev/null
+++ b/crypto/modes/ocb128.c
@@ -0,0 +1,587 @@
+/* ====================================================================
+ * Copyright (c) 2014 The OpenSSL Project. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * 3. All advertising materials mentioning features or use of this
+ * software must display the following acknowledgment:
+ * "This product includes software developed by the OpenSSL Project
+ * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ * endorse or promote products derived from this software without
+ * prior written permission. For written permission, please contact
+ * openssl-core@openssl.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ * nor may "OpenSSL" appear in their names without prior written
+ * permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ * acknowledgment:
+ * "This product includes software developed by the OpenSSL Project
+ * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ * ====================================================================
+ */
+
+#include <string.h>
+#include <openssl/crypto.h>
+#include "modes_lcl.h"
+
+union ublock {
+ unsigned char *chrblk;
+ OCB_BLOCK *ocbblk;
+};
+
+/*
+ * Calculate the number of binary trailing zero's in any given number
+ */
+static u32 ocb_ntz(u64 n)
+{
+ u32 cnt = 0;
+
+ /*
+ * We do a right-to-left simple sequential search. This is surprisingly
+ * efficient as the distribution of trailing zeros is not uniform,
+ * e.g. the number of possible inputs with no trailing zeros is equal to
+ * the number with 1 or more; the number with exactly 1 is equal to the
+ * number with 2 or more, etc. Checking the last two bits covers 75% of
+ * all numbers. Checking the last three covers 87.5%
+ */
+ while (!(n & 1)) {
+ n >>= 1;
+ cnt++;
+ }
+ return cnt;
+}
+
+/*
+ * Shift a block of 16 bytes left by shift bits
+ */
+static void ocb_block_lshift(OCB_BLOCK *in, size_t shift, OCB_BLOCK *out)
+{
+ unsigned char shift_mask;
+ int i;
+ unsigned char mask[15];
+ union ublock locin;
+ union ublock locout;
+
+ locin.ocbblk = in;
+ locout.ocbblk = out;
+
+ shift_mask = 0xff;
+ shift_mask <<= (8 - shift);
+ for (i = 15; i >= 0; i--) {
+ if (i > 0) {
+ mask[i - 1] = locin.chrblk[i] & shift_mask;
+ mask[i - 1] >>= 8 - shift;
+ }
+ locout.chrblk[i] = locin.chrblk[i] << shift;
+
+ if (i != 15) {
+ locout.chrblk[i] ^= mask[i];
+ }
+ }
+}
+
+/*
+ * Perform a "double" operation as per OCB spec
+ */
+static void ocb_double(OCB_BLOCK *in, OCB_BLOCK *out)
+{
+ unsigned char mask;
+ union ublock locin;
+ union ublock locout;
+
+ locin.ocbblk = in;
+ locout.ocbblk = out;
+
+ /*
+ * Calculate the mask based on the most significant bit. There are more
+ * efficient ways to do this - but this way is constant time
+ */
+ mask = locin.chrblk[0] & 0x80;
+ mask >>= 7;
+ mask *= 135;
+
+ ocb_block_lshift(in, 1, out);
+
+ locout.chrblk[15] ^= mask;
+}
+
+/*
+ * Perform an xor on in1 and in2 - each of len bytes. Store result in out
+ */
+static void ocb_block_xor(const unsigned char *in1,
+ const unsigned char *in2, size_t len,
+ unsigned char *out)
+{
+ size_t i;
+ for (i = 0; i < len; i++) {
+ out[i] = in1[i] ^ in2[i];
+ }
+}
+
+/*
+ * Lookup L_index in our lookup table. If we haven't already got it we need to
+ * calculate it
+ */
+static OCB_BLOCK *ocb_lookup_l(OCB128_CONTEXT * ctx, size_t index)
+{
+ if (index <= ctx->l_index) {
+ return ctx->l + index;
+ }
+
+ /* We don't have it - so calculate it */
+ ctx->l_index++;
+ if (ctx->l_index == ctx->max_l_index) {
+ ctx->max_l_index *= 2;
+ ctx->l = OPENSSL_realloc(ctx->l, ctx->max_l_index * sizeof(OCB_BLOCK));
+ if (!ctx->l)
+ return NULL;
+ }
+ ocb_double(ctx->l + (index - 1), ctx->l + index);
+
+ return ctx->l + index;
+}
+
+/*
+ * Encrypt a block from |in| and store the result in |out|
+ */
+static void ocb_encrypt(OCB128_CONTEXT *ctx, OCB_BLOCK *in, OCB_BLOCK *out, void *keyenc)
+{
+ union ublock locin;
+ union ublock locout;
+
+ locin.ocbblk = in;
+ locout.ocbblk = out;
+
+ ctx->encrypt(locin.chrblk, locout.chrblk, keyenc);
+}
+
+/*
+ * Decrypt a block from |in| and store the result in |out|
+ */
+static void ocb_decrypt(OCB128_CONTEXT *ctx, OCB_BLOCK *in, OCB_BLOCK *out, void *keydec)
+{
+ union ublock locin;
+ union ublock locout;
+
+ locin.ocbblk = in;
+ locout.ocbblk = out;
+
+ ctx->decrypt(locin.chrblk, locout.chrblk, keydec);
+}
+
+/*
+ * Create a new OCB128_CONTEXT
+ */
+OCB128_CONTEXT *CRYPTO_ocb128_new(void *keyenc, void *keydec,
+ block128_f encrypt, block128_f decrypt)
+{
+ OCB128_CONTEXT *octx;
+ int ret;
+
+ if ((octx = (OCB128_CONTEXT *) OPENSSL_malloc(sizeof(OCB128_CONTEXT)))) {
+ ret = CRYPTO_ocb128_init(octx, keyenc, keydec, encrypt, decrypt);
+ if (ret)
+ return octx;
+ OPENSSL_free(octx);
+ }
+
+ return NULL;
+}
+
+/*
+ * Initialise an existing OCB128_CONTEXT
+ */
+int CRYPTO_ocb128_init(OCB128_CONTEXT *ctx, void *keyenc, void *keydec,
+ block128_f encrypt, block128_f decrypt)
+{
+ /* Clear everything to NULLs */
+ memset(ctx, 0, sizeof(*ctx));
+
+ ctx->l_index = 0;
+ ctx->max_l_index = 1;
+ ctx->l = OPENSSL_malloc(ctx->max_l_index * 16);
+ if (!ctx->l)
+ return 0;
+
+ /*
+ * We set both the encryption and decryption key schedules - decryption
+ * needs both. Don't really need decryption schedule if only doing
+ * encryption - but it simplifies things to take it anyway
+ */
+ ctx->encrypt = encrypt;
+ ctx->decrypt = decrypt;
+ ctx->keyenc = keyenc;
+ ctx->keydec = keydec;
+
+ /* L_* = ENCIPHER(K, zeros(128)) */
+ ocb_encrypt(ctx, &ctx->l_star, &ctx->l_star, ctx->keyenc);
+
+ /* L_$ = double(L_*) */
+ ocb_double(&ctx->l_star, &ctx->l_dollar);
+
+ /* L_0 = double(L_$) */
+ ocb_double(&ctx->l_dollar, ctx->l);
+
+ return 1;
+}
+
+/*
+ * Copy an OCB128_CONTEXT object
+ */
+int CRYPTO_ocb128_copy_ctx(OCB128_CONTEXT * dest, OCB128_CONTEXT * src,
+ void *keyenc, void *keydec)
+{
+ memcpy(dest, src, sizeof(OCB128_CONTEXT));
+ if (keyenc)
+ dest->keyenc = keyenc;
+ if (keydec)
+ dest->keydec = keydec;
+ if (src->l) {
+ dest->l = OPENSSL_malloc(src->max_l_index * 16);
+ if (!dest->l)
+ return 0;
+ memcpy(dest->l, src->l, (src->l_index + 1) * 16);
+ }
+ return 1;
+}
+
+/*
+ * Set the IV to be used for this operation. Must be 1 - 15 bytes.
+ */
+int CRYPTO_ocb128_setiv(OCB128_CONTEXT * ctx, const unsigned char *iv,
+ size_t len, size_t taglen)
+{
+ unsigned char ktop[16], tmp[16], mask;
+ unsigned char stretch[24], nonce[16];
+ size_t bottom, shift;
+ union ublock offset;
+
+ offset.ocbblk = &ctx->offset;
+
+ /*
+ * Spec says IV is 120 bits or fewer - it allows non byte aligned lengths.
+ * We don't support this at this stage
+ */
+ if ((len > 15) || (len < 1) || (taglen > 16) || (taglen < 1)) {
+ return -1;
+ }
+
+ /* Nonce = num2str(TAGLEN mod 128,7) || zeros(120-bitlen(N)) || 1 || N */
+ nonce[0] = ((taglen * 8) % 128) << 1;
+ memset(nonce + 1, 0, 15);
+ memcpy(nonce + 16 - len, iv, len);
+ nonce[15 - len] |= 1;
+
+ /* Ktop = ENCIPHER(K, Nonce[1..122] || zeros(6)) */
+ memcpy(tmp, nonce, 16);
+ tmp[15] &= 0xc0;
+ ctx->encrypt(tmp, ktop, ctx->keyenc);
+
+ /* Stretch = Ktop || (Ktop[1..64] xor Ktop[9..72]) */
+ memcpy(stretch, ktop, 16);
+ ocb_block_xor(ktop, ktop + 1, 8, stretch + 16);
+
+ /* bottom = str2num(Nonce[123..128]) */
+ bottom = nonce[15] & 0x3f;
+
+ /* Offset_0 = Stretch[1+bottom..128+bottom] */
+ shift = bottom % 8;
+ ocb_block_lshift((OCB_BLOCK *)(stretch + (bottom / 8)), shift, &ctx->offset);
+ mask = 0xff;
+ mask <<= 8 - shift;
+ offset.chrblk[15] |= (*(stretch + (bottom / 8) + 16) & mask) >> (8 - shift);
+
+ return 1;
+}
+
+/*
+ * Provide any AAD. This can be called multiple times. Only the final time can
+ * have a partial block
+ */
+int CRYPTO_ocb128_aad(OCB128_CONTEXT * ctx, const unsigned char *aad,
+ size_t len)
+{
+ u64 all_num_blocks, num_blocks;
+ u64 i;
+ OCB_BLOCK tmp1;
+ OCB_BLOCK tmp2;
+ int last_len;
+
+ /* Calculate the number of blocks of AAD provided now, and so far */
+ num_blocks = len / 16;
+ all_num_blocks = num_blocks + ctx->blocks_hashed;
+
+ /* Loop through all full blocks of AAD */
+ for (i = ctx->blocks_hashed + 1; i <= all_num_blocks; i++) {
+ OCB_BLOCK *lookup;
+ OCB_BLOCK *aad_block;
+
+ /* Offset_i = Offset_{i-1} xor L_{ntz(i)} */
+ lookup = ocb_lookup_l(ctx, ocb_ntz(i));
+ if (!lookup)
+ return 0;
+ ocb_block16_xor(&ctx->offset_aad, lookup, &ctx->offset_aad);
+
+ /* Sum_i = Sum_{i-1} xor ENCIPHER(K, A_i xor Offset_i) */
+ aad_block = (OCB_BLOCK *) (aad + ((i - ctx->blocks_hashed - 1) * 16));
+ ocb_block16_xor(&ctx->offset_aad, aad_block, &tmp1);
+ ocb_encrypt(ctx, &tmp1, &tmp2, ctx->keyenc);
+ ocb_block16_xor(&ctx->sum, &tmp2, &ctx->sum);
+ }
+
+ /*
+ * Check if we have any partial blocks left over. This is only valid in the
+ * last call to this function
+ */
+ last_len = len % 16;
+
+ if (last_len > 0) {
+ /* Offset_* = Offset_m xor L_* */
+ ocb_block16_xor(&ctx->offset_aad, &ctx->l_star, &ctx->offset_aad);
+
+ /* CipherInput = (A_* || 1 || zeros(127-bitlen(A_*))) xor Offset_* */
+ memset((void *)&tmp1, 0, 16);
+ memcpy((void *)&tmp1, aad + (num_blocks * 16), last_len);
+ ((unsigned char *)&tmp1)[last_len] = 0x80;
+ ocb_block16_xor(&ctx->offset_aad, &tmp1, &tmp2);
+
+ /* Sum = Sum_m xor ENCIPHER(K, CipherInput) */
+ ocb_encrypt(ctx, &tmp2, &tmp1, ctx->keyenc);
+ ocb_block16_xor(&ctx->sum, &tmp1, &ctx->sum);
+ }
+
+ ctx->blocks_hashed = all_num_blocks;
+
+ return 1;
+}
+
+/*
+ * Provide any data to be encrypted. This can be called multiple times. Only
+ * the final time can have a partial block
+ */
+int CRYPTO_ocb128_encrypt(OCB128_CONTEXT * ctx,
+ const unsigned char *in, unsigned char *out,
+ size_t len)
+{
+ u64 i;
+ u64 all_num_blocks, num_blocks;
+ OCB_BLOCK tmp1;
+ OCB_BLOCK tmp2;
+ OCB_BLOCK pad;
+ int last_len;
+
+ /*
+ * Calculate the number of blocks of data to be encrypted provided now, and
+ * so far
+ */
+ num_blocks = len / 16;
+ all_num_blocks = num_blocks + ctx->blocks_processed;
+
+ /* Loop through all full blocks to be encrypted */
+ for (i = ctx->blocks_processed + 1; i <= all_num_blocks; i++) {
+ OCB_BLOCK *lookup;
+ OCB_BLOCK *inblock;
+ OCB_BLOCK *outblock;
+
+ /* Offset_i = Offset_{i-1} xor L_{ntz(i)} */
+ lookup = ocb_lookup_l(ctx, ocb_ntz(i));
+ if (!lookup)
+ return 0;
+ ocb_block16_xor(&ctx->offset, lookup, &ctx->offset);
+
+ /* C_i = Offset_i xor ENCIPHER(K, P_i xor Offset_i) */
+ inblock = (OCB_BLOCK *) (in + ((i - ctx->blocks_processed - 1) * 16));
+ ocb_block16_xor(&ctx->offset, inblock, &tmp1);
+ ocb_encrypt(ctx, &tmp1, &tmp2, ctx->keyenc);
+ outblock =
+ (OCB_BLOCK *) (out + ((i - ctx->blocks_processed - 1) * 16));
+ ocb_block16_xor(&ctx->offset, &tmp2, outblock);
+
+ /* Checksum_i = Checksum_{i-1} xor P_i */
+ ocb_block16_xor(&ctx->checksum, inblock, &ctx->checksum);
+ }
+
+ /*
+ * Check if we have any partial blocks left over. This is only valid in the
+ * last call to this function
+ */
+ last_len = len % 16;
+
+ if (last_len > 0) {
+ /* Offset_* = Offset_m xor L_* */
+ ocb_block16_xor(&ctx->offset, &ctx->l_star, &ctx->offset);
+
+ /* Pad = ENCIPHER(K, Offset_*) */
+ ocb_encrypt(ctx, &ctx->offset, &pad, ctx->keyenc);
+
+ /* C_* = P_* xor Pad[1..bitlen(P_*)] */
+ ocb_block_xor(in + (len / 16) * 16, (unsigned char *)&pad, last_len,
+ out + (num_blocks * 16));
+
+ /* Checksum_* = Checksum_m xor (P_* || 1 || zeros(127-bitlen(P_*))) */
+ memset((void *)&tmp1, 0, 16);
+ memcpy((void *)&tmp1, in + (len / 16) * 16, last_len);
+ ((unsigned char *)(&tmp1))[last_len] = 0x80;
+ ocb_block16_xor(&ctx->checksum, &tmp1, &ctx->checksum);
+ }
+
+ ctx->blocks_processed = all_num_blocks;
+
+ return 1;
+}
+
+/*
+ * Provide any data to be decrypted. This can be called multiple times. Only
+ * the final time can have a partial block
+ */
+int CRYPTO_ocb128_decrypt(OCB128_CONTEXT * ctx,
+ const unsigned char *in, unsigned char *out,
+ size_t len)
+{
+ u64 i;
+ u64 all_num_blocks, num_blocks;
+ OCB_BLOCK tmp1;
+ OCB_BLOCK tmp2;
+ OCB_BLOCK pad;
+ int last_len;
+ /*
+ * Calculate the number of blocks of data to be decrypted provided now, and
+ * so far
+ */
+ num_blocks = len / 16;
+ all_num_blocks = num_blocks + ctx->blocks_processed;
+
+ /* Loop through all full blocks to be decrypted */
+ for (i = ctx->blocks_processed + 1; i <= all_num_blocks; i++) {
+ OCB_BLOCK *inblock;
+ OCB_BLOCK *outblock;
+
+ /* Offset_i = Offset_{i-1} xor L_{ntz(i)} */
+ OCB_BLOCK *lookup = ocb_lookup_l(ctx, ocb_ntz(i));
+ if (!lookup)
+ return 0;
+ ocb_block16_xor(&ctx->offset, lookup, &ctx->offset);
+
+ /* P_i = Offset_i xor DECIPHER(K, C_i xor Offset_i) */
+ inblock = (OCB_BLOCK *) (in + ((i - ctx->blocks_processed - 1) * 16));
+ ocb_block16_xor(&ctx->offset, inblock, &tmp1);
+ ocb_decrypt(ctx, &tmp1, &tmp2, ctx->keydec);
+ outblock = (OCB_BLOCK *) (out + ((i - ctx->blocks_processed - 1) * 16));
+ ocb_block16_xor(&ctx->offset, &tmp2, outblock);
+
+ /* Checksum_i = Checksum_{i-1} xor P_i */
+ ocb_block16_xor(&ctx->checksum, outblock, &ctx->checksum);
+ }
+
+ /*
+ * Check if we have any partial blocks left over. This is only valid in the
+ * last call to this function
+ */
+ last_len = len % 16;
+
+ if (last_len > 0) {
+ /* Offset_* = Offset_m xor L_* */
+ ocb_block16_xor(&ctx->offset, &ctx->l_star, &ctx->offset);
+
+ /* Pad = ENCIPHER(K, Offset_*) */
+ ocb_encrypt(ctx, &ctx->offset, &pad, ctx->keyenc);
+
+ /* P_* = C_* xor Pad[1..bitlen(C_*)] */
+ ocb_block_xor(in + (len / 16) * 16, (unsigned char *)&pad, last_len,
+ out + (num_blocks * 16));
+
+ /* Checksum_* = Checksum_m xor (P_* || 1 || zeros(127-bitlen(P_*))) */
+ memset((void *)&tmp1, 0, 16);
+ memcpy((void *)&tmp1, out + (len / 16) * 16, last_len);
+ ((unsigned char *)(&tmp1))[last_len] = 0x80;
+ ocb_block16_xor(&ctx->checksum, &tmp1, &ctx->checksum);
+ }
+
+ ctx->blocks_processed = all_num_blocks;
+
+ return 1;
+}
+
+/*
+ * Calculate the tag and verify it against the supplied tag
+ */
+int CRYPTO_ocb128_finish(OCB128_CONTEXT * ctx, const unsigned char *tag,
+ size_t len)
+{
+ OCB_BLOCK tmp1, tmp2;
+
+ /*Tag = ENCIPHER(K, Checksum_* xor Offset_* xor L_$) xor HASH(K,A) */
+ ocb_block16_xor(&ctx->checksum, &ctx->offset, &tmp1);
+ ocb_block16_xor(&tmp1, &ctx->l_dollar, &tmp2);
+ ocb_encrypt(ctx, &tmp2, &tmp1, ctx->keyenc);
+ ocb_block16_xor(&tmp1, &ctx->sum, &ctx->tag);
+
+ if (len > 16 || len < 1) {
+ return -1;
+ }
+
+ /* Compare the tag if we've been given one */
+ if (tag)
+ return CRYPTO_memcmp(&ctx->tag, tag, len);
+ else
+ return -1;
+}
+
+/*
+ * Retrieve the calculated tag
+ */
+int CRYPTO_ocb128_tag(OCB128_CONTEXT * ctx, unsigned char *tag, size_t len)
+{
+ if (len > 16 || len < 1) {
+ return -1;
+ }
+
+ /* Calculate the tag */
+ CRYPTO_ocb128_finish(ctx, NULL, 0);
+
+ /* Copy the tag into the supplied buffer */
+ memcpy(tag, &ctx->tag, len);
+
+ return 1;
+}
+
+/*
+ * Release all resources
+ */
+void CRYPTO_ocb128_cleanup(OCB128_CONTEXT * ctx)
+{
+ if (ctx) {
+ if (ctx->l) {
+ OPENSSL_cleanse(ctx->l, ctx->max_l_index * 16);
+ OPENSSL_free(ctx->l);
+ }
+ OPENSSL_cleanse(ctx, sizeof(*ctx));
+ }
+}
